21248417 has 2 divisors, whose sum is σ = 21248418. Its totient is φ = 21248416.

The previous prime is 21248411. The next prime is 21248429. The reversal of 21248417 is 71484212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13608721 + 7639696 = 3689^2 + 2764^2 .

It is a cyclic number.

It is not a de Polignac number, because 21248417 - 2⁴ = 21248401 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21248417.

It is not a weakly prime, because it can be changed into another prime (21248411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10624208 + 10624209.

It is an arithmetic number, because the mean of its divisors is an integer number (10624209).

Almost surely, 2^21248417 is an apocalyptic number.

It is an amenable number.

21248417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21248417 is an equidigital number, since it uses as much as digits as its factorization.

21248417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3584, while the sum is 29.

The square root of 21248417 is about 4609.6005249913. The cubic root of 21248417 is about 276.9760348010.

The spelling of 21248417 in words is "twenty-one million, two hundred forty-eight thousand, four hundred seventeen".